Ramona Singer's Daughter Avery Has Been Supporting Her Through Split with Mario

Ramona Singer's 19-year-old daughter Avery isn't happy with her father, the Real Housewives of New York star tells PEOPLE.

"Mario's behavior is embarrassing to me and my daughter," says Singer, 57, about her husband of 22 years. "We aren't embarrassed. We are embarrassed for him."

Singer, who says she kicked Mario out on July 24, announced the split on Twitter on Aug. 7, several days after Mario and his alleged girlfriend, Kasey Dexter, 32, had been caught on camera by a tabloid, which found them dining at a New York City restaurant.

Singer says she gave Mario "many chances," following a cheating scandal earlier this year, which prompted her to file for divorce in January. She said she had had enough when she learned he had allegedly reconnected with Dexter this summer.

Things came to a head on July 23 when she confronted Mario about Dexter in their therapist's office. She says he denied that he had been in contact with her. When she pushed him about it the next day, he confessed that he had seen Dexter.

"I told Mario it's over because he lied to me about still being in contact with this Kasey. I said, 'You are a liar. You are a betrayer. I don't want you in my life anymore. I tried to make it work for a year and that's it. I'm done.' "

She further states: "My daughter even said to him, 'If you don't want to be with Mommy, then do the right thing and split up.' She's angry at him. It's upsetting."